fasstr: add_cumulative_yield – R documentation

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add_cumulative_yield

Add a daily cumulative water yield column to daily flows

Description

Add a column of rolling daily cumulative water yields on an annual basis to a daily streamflow data set. Adds the water yields from each day with the previous day(s) for each year, in units of millimetres. Converts cumulative discharge to a depth of water based on the upstream drainage basin area from basin_area argument. The cumulative flows restart every year and are only calculated in years with complete data.

Usage

add_cumulative_yield(
  data,
  dates = Date,
  values = Value,
  groups = STATION_NUMBER,
  station_number,
  basin_area,
  water_year_start = 1
)

Arguments

`data`	Data frame of daily data that contains columns of dates, flow values, and (optional) groups (e.g. station numbers). Leave blank if using `station_number` argument.
`dates`	Name of column in `data` that contains dates formatted YYYY-MM-DD. Only required if dates column name is not 'Date' (default). Leave blank if using `station_number` argument.
`values`	Name of column in `data` that contains numeric flow values, in units of cubic metres per second. Only required if values column name is not 'Value' (default). Leave blank if using `station_number` argument.
`groups`	Name of column in `data` that contains unique identifiers for different data sets, if applicable. Only required if groups column name is not 'STATION_NUMBER'. Function will automatically group by a column named 'STATION_NUMBER' if present. Remove the 'STATION_NUMBER' column beforehand to remove this grouping. Leave blank if using `station_number` argument.
`station_number`	Character string vector of seven digit Water Survey of Canada station numbers (e.g. `"08NM116"`) of which to extract daily streamflow data from a HYDAT database. Requires `tidyhydat` package and a HYDAT database. Leave blank if using `data` argument.
`basin_area`	Upstream drainage basin area, in square kilometres, to apply to observations. Three options: (1) Leave blank if `groups` is STATION_NUMBER with HYDAT station numbers to extract basin areas from HYDAT. (2) A single numeric value to apply to all observations. (3) List each basin area for each group/station in groups (can override HYDAT value if listed) as such `c("08NM116" = 795, "08NM242" = 10)`. If group is not listed the HYDAT area will be applied if it exists, otherwise it will be `NA`.
`water_year_start`	Numeric value indicating the month (`1` through `12`) of the start of water year for analysis. Default `1`.

Value

A tibble data frame of the source data with an additional column:

Cumul_Yield_mm

cumulative yield flows for each day for each year, in units of millimetres

Examples

# Run if HYDAT database has been downloaded (using tidyhydat::download_hydat())
if (file.exists(tidyhydat::hy_downloaded_db())) {

# Add a column based on water years starting in August
add_cumulative_yield(station_number = "08NM116", 
                     water_year_start = 8)
                     
# Add a column based on water years starting in August with a custom basin area to calculate yield
add_cumulative_yield(station_number = "08NM116", 
                     water_year_start = 8,
                     basin_area = 800)
                     
}

fasstr

Analyze, Summarize, and Visualize Daily Streamflow Data

v0.3.2

Apache License 2.0

Authors

Jon Goetz [aut, cre] (<https://orcid.org/0000-0002-4993-1119>), Carl James Schwarz [aut], Robin Pike [ctb], Province of British Columbia [cph]

Initial release